Thread-milling machine



C. H. SCHURR AND E. J. LEES.

THREAD MILLING MACHINE.

APPLICATION FILED IAN. I2, 191s.

Patented Oct. 11.79 1922.

4 SHEETS-SHEET I.

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THREAD MILLING MACHINE. APPLICATION FILED IAII.I2, 191s.

1942962@ Pammed @on E7, R922@ 4 SHEETS-SHEET 2.

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In.. Il lll C. H. SCHUHE AND E. l. LEES.

THREAD MILLING MCHHL.

APPUCMION HLED1AN,12,1918.

L, atented Oct. L?, 1922i,

SHEES-SHEET 3.

C. H. SCHUHE AND E. 1. LEES.

THREAD MILLING MACHINE.

APPLICATION FILED IAN. I2. ISIS. 194393 @$36. Fatemi-ed Oct. I?. 1922.

'Patented @et i7, 1922..

narran eras hddttt PATENT @FFEQO CHARLES H.y SCHURR AND ERNEST J'. LEES,0F CLEVELAND, OHIO, ASSIGNQBS T0- THE LEES-BRADNER C0., OF CLEVELAND,QHIO.

. waan-MILLING atacante.

rll`hread-Milling Machines, of which the following 4is a specification,the principle of the invention being herein explained and -the best modein which we have contemplated applying that principle, so as to distinish it from other inventions.

ur invention pertains to improvements in a thread milling machine andmore particularl. to changes in the relatlve arrangement, shape andfunction of certain parts .which either mechanically. coact with thelead screw or have. some other practical indirect association therewith.

The improvements declared by this application are four in number, first,an arrangement which places the lead `screw directly underneathlongitudinal ways upon the bed of the machine so that such screw issheltered and protected from above particularly against the deposit ofgrit and other sediment, the collection of which is attendant upon theworking operation of the machine; second, the provision of anindependent longer and more durable thrust bearing for the lead screwwhich is located between the two -end bearings ordinarily till nowrelied upon; third, an arrangement whereby a saddle which carriesthe-swivel head and is automatically moved by the lead screw is causedto have telescopic connection with the tail stock so that the relativelongitudinal movement of the two is considerably increased; fourth, theprovision of duplex means for controlling.the operative connection ofthe lead screw and saddle, especially in the provision of means forabsolutely locking the two together in addition to the frictional holdupon which reliancev has heretofore been placed.

With the foregoing and other objects in view the invention consists ofthe novel construction, combination and arrangement of parts ashereinafter more specifically described and illustrated in' theaccompanying drawings, wherein is shown an embodiment of the invention,but it is to be understood that changes, variations and modificationscan be resorted to which come vwithin the scope of the claims hereuntoappended.

Adverting to the drawings:

Figure I--is a front elevation of a thread millin machine embodying -ourinvention with t e tail stock in a certain position.-

Fi ure II is a corresponding view showing t e tail stock moved to aposition somewhat nearer therhead stock to exemplify its telescopicassociation with the saddle.

Figure-Hl is a partial plan view of that portion of the machine whichincludes the telescopic arrangement of the saddle and tail stockillustrated-in Figure H.

vFigure IV is a vertical cross-section of the machine showing theposition of the lead screw directly underneath the ways formed upon thelongitudinal front.

Figure V is a right end view showing parts of the tail stock in sectionwhereby the telescopic connection is otherwise revealed.

Figure VI is an enlarged vertical crosssection on line VI-VI of Figure Ishowing certain operative parts in end elevation with thev swivel headremoved.

'Figure VH is a vertical longitudinal section on line VI-VII of FigureVI.

Figure VIH is an oblique-section on line VIII-V IH of Figure Vl.

rIhe machine is supported upon a suitable bed 1 provided above with asli-deway 2 along the longitudinal front of the bed. An interjacent areaof the slideway -is formed as an upwardly projecting guideway 3. rlhepurpose of .both ways will hereinafter appear. One end of the bedsupports the head stock 4 on which atrain of gearing designated entirelyby the numeral 5 communicates power to a lead screw 6 which extends theentire length of the machine and is supported at opposite ends thereofin suitable bearings 7 and 8. Inasmuch as the manner of making the headstock so as to effect the harmonious I against poa-` dispositionthereupon of chips, grit and sediment which would be likely eventuallyto in-Y jure the threads thereon. This feature while simple is a usefulpractical advantagev and The end thrust required to be reckoned withinthe lead screw bearings has frequently occasioned trouble, partlybecause of its occasional severity and partly because at the location ofthe bearing which I have designated by the numeral. 7 insufficient spacewas afforded for the accommodation of an end thrust. bearing largeenough and strong enoughto meet the needs. Vitli this in'mind wehavethought to provide auxiliaryend thrust bearing surfaces between thebearings 7 and 8 which are sufficiently removed in a direction towardthe tail stock. The construction. comprises a pair of spaced collars 9which are pinned to the shaft 6 on opposite sides of the additional endthrust bearing 10. Brass washers 11 also appear interposed between thefaced ends of the bearing and the collars.

Movable upon the guideway 3 is a saddle 12 adapted to support the swivelcutter 4head inl conformit with the idea which constitutes the thirdfeature of our invention.

That end of the saddle 12 which is furthest from the head stock 4 isbeveled off at 13. A tail stock 14 is movable upon the slideway 2 andowing to itsbeing hollowed at 15 is enabled to straddle the smaller end13 of thev saddle or to have what is in the nature of a telescopic .fittherewith. The advantage of such van arrangement is that the tail stockmay be mcved considerably nearer the head stock 'Witheet interferencewith the saddle. of the tail stock are indicated in Figures I and IIrespectively andthe manner in which the tail stock is intersectedfby thereduced extremity of the saddle will be further evidenced uponinspection of Figures III and V. The movement of the tail stock may beaccomplished in the ordinary way by turning a hand wheel 16 which inturn rotates a pinion 17 in engagement with a rack 18' which is carriedalong the front of the machine.

In machines of this character it is desired frequently to reverse thecutter head independentlyof the :automaticV drive or longitudinaltraverse movement thereof by mea-ns of the lead screw. To this end ithas beenv common in the art to loosen certain parts so as to enable idlemovement ofthe supporting saddle irrespective of any movement on thepart of the lead screw. Till now, so far as our knowledge extends, thiswas accomplished by the loosening of a frictional hold which obtainedduring the automatic working traverse as between the lead screw and acoacting internally threaded The two nearl v extreme ositions sleevecarried by the saddle. We'have discovered that such frictional hold wasnecessarily coarse and insufliciently reliable where absolute precisionwas desirable or necessaryk and'laccordingly have provided an additional'firmer connection between the lead screw valso .the frictional.engagement 'is suilicient because the cuttingengagement is less severewhen the frictional engagement is to be relied upon. Suppose a piece tohave been cut. taken out and found not `'small' enough, necessitatingthat it be placed back on the machine 'for recutting. No identificationmarks being on the shaft the relation of the threads to the position ofthe cutter is'not correctly ascertainable. The precise position. of thecutter is not known. In such a case the positive or lock connection isre leased and the nut rotated'so as to move the cutter lengthwise ofthebed and then after it is properly located the frictional hold willanswer satisfactorily because the subsequent finishing cut iscomparatively fine. Rotatably mounted in a hanger depending from thesaddle 12 is an internally threaded sleeve 19 adapted to cooperate withthelead screw 6. This sleevefis anged at one end at 20 and such flangecarries'on one side a beveled gear 21 and on theother side an auxiliarysleeve 22 the fixed relation being effected by means of pins 23. Theauxiliary sleeve 22 is provided with circumferential notches 24 seen inFigures VI and VIII, the purpose of which will hereinafter becomeyapparent. In screw threaded connection with a boss 25, formed on theunder side of the hanger, is an adjustable nut having the outer end ofits stem provided with a handle 26, the inner endl of which is adaptedto engagea clamping shoe 27 disposed in a suitable slot 28 and movableinto and out of an annulan 115 groove 29 fashioned in the sleeve 19.By'. this arrangement the clamping shoe 27 may be caused frictionallytoengage the sleeve to prevent its rotation and therefore to cause itsaxial movement whenever the lead screw 120 y6 turns. l A thumb screw 30passes through a projection 31 on the hanger in such a manner that theinner extremity 32 of the screw may be entered into any one of thecircumferential notches 24 and thereby the addi- 125 fore a bevel pinion35 which is carried'on 130 the opposite end of the shaft in mesh withthe beveled gear 21. This is the usual contrivance by means of which,after the sleeve 19 is loosened. it may be rotated about the screw so asto accomplish the return of the saddle in a direction toward the tailstock.

The arrangement according to which the lead screw is disposed directlyunderneath the guideway 3 cf the saddle 12 eases and perfects the actionwhich determines the lead because the thrust therealong is more nearlyparallel owing to the fact that the lead screw is in the same verticalplane as the center line of the saddle. In this Way accessibility,durability and accuracy are had. Less friction is encountered where theguideway and slideway are brought close together particularly whensuperposed as We have disclosed than if they were separated so that one`was along the front of the machine and the other along the back thereof.

lVe claim:

l. A thread milling machine comprising a bed formed with Ways, Work andtool holders thereon, a saddle supporting one of said holders andmovable upon said Ways. driving means, a lead screw operativelyconnecting said driving means Wit-h said saddle, friction means forcontrolling said connection and distinct means adapted to lock saidconnection.

2. A thread milling machine comprising a bed formed with Ways, Work andtool holders thereon, a saddle supporting said too] holder and movableupon said Ways, an internally threaded sleeve mounted in said saddle,driving means, a lead screw cooperating with said sleeve and operativelyconnected with said driving means to effect the automatictraverse ofsaid saddle, amd a locking device including parts carried by said saddleand sleeve respectively to secure the same together.

3. A thread milling machine comprising a bed formed with Ways, Work andtool holders thereon7 a saddle supporting said tool holder and movableupon said Ways, an internally threaded sleeve rotatably mounted in saidsaddle and fashioned With circularly arranged notches, driving means, alead screw cooperating With said sleeve and operatively connected withsaid drivin means to effect the automatic traverse of sai saddle, meansfor frictionally binding said sleeve and saddle together, and meanscarried by said saddle and adapted to project into one of said notcheswhereby absolutely to lock said sleeve and saddle together.

Signed by us, this 28th day of December,

CHARLES H. SCHURR. ERNEST J. LEES'.

